CN103913772A - Microseism event forward modeling method based on reservoir geomechanical parameters - Google Patents

Abstract

The invention provides a microseism event forward modeling method based on reservoir geomechanical parameters. The microseism event forward modeling method based on the reservoir geomechanical parameters comprises the steps that pressure valuation is conducted on initial hydraulic fracturing, and the finite element method is used for model simulation; the stress of a rock unit at each specific moment is calculated according to time variation; whether the current rock unit is fractured or not is judged according to a stress calculation result in combination with rock fracturing criteria; porosity parameters are calculated; if the rock unit fractures, the magnitude of a focus is calculated in combination with a microseism focal mechanism; simulation at all moments is completed. According to the microseism event forward modeling method based on the reservoir geomechanical parameters, the calculation result can truthfully reflect the actual change conditions of a subsurface reservoir, and the method can be used for prediction of a microseism event in the process of subsurface cracking and fracturing.

Description

Microearthquake event the Forward Modeling based on reservoir geology mechanics parameter

Technical field

The present invention relates to the simulation of the microearthquake in waterfrac treatment simulation and method of seismic prospecting in petroleum engineering, particularly relate to a kind of microearthquake event the Forward Modeling based on reservoir geology mechanics parameter.

Background technology

Waterfrac treatment is the important means that improves the unconventional petroleum resources output such as fine and close oil gas, shale gas.In the process of pressure break, monitoring fracturing effect, perfect to the proposition of pressure break scheme, for improving output, reduce costs and have great significance.Microseismic is the current approved unique effective means that is used for Real-Time Monitoring fracturing effect.In the process to the water filling of low-permeability reservoir or gas injection, can cause the movement of hydrodynamic pressure leading edge and the variation of pore-fluid pressure, thereby cause microearthquake event.Monitor by microearthquake, can adjust in real time, optimizing design scheme, effectively improve the rate of oil and gas recovery, realize the scientific management of the whole development in oil field.By the microearthquake monitoring under waterfrac treatment, can effectively follow the trail of pressure break scope, fracture azimuth and size, location, the effect of objective appraisal fracturing engineering, especially by series crack attributive analysis, the structure trend of location major fracture, and the distribution of secondary fracture, approximate treatment goes out the length, width in crack, highly; Monitor by microearthquake, can carry out imaging to rock interior fluid front.Reservoir engineer, by the analysis of fracture imaging and driving leading edge sweep conditions, provides effective guidance to next step production development.For primary development, fracture azimuth and distribution range will contribute to develop most effectively mobile oil gas from well accurately.For the secondary development of reservoir, contribute to determine oil recovery well location, improve tar productivity, cost-saving, increase benefit.

The mechanism producing for microearthquake is at present understood not, make microearthquake data in actual applications effect need to be further improved.The conventional positive artistic skills art of microearthquake is that hypothesis focus and propagation medium are known, when studying it and walking and the method for the propagation law such as amplitude and frequency, not in conjunction with reservoir geology mechanics parameter.We have invented a kind of new microearthquake event the Forward Modeling based on reservoir geology mechanics parameter for this reason, have solved above technical matters.

Summary of the invention

The object of this invention is to provide a kind of microearthquake event the Forward Modeling based on reservoir geology mechanics parameter of the prediction that can carry out microseismic event in subterranean fracture and fracturing process.

Object of the present invention can be achieved by the following technical measures: the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter, should the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter comprise: step 1, for the pressure assignment of initial waterfrac treatment, use finite element method (FEM) to carry out modeling; Step 2, changes the rock element stress calculating of carrying out each particular moment according to the time; Step 3, according to stress calculating results, in conjunction with criterion in rock, judges whether current rock unit breaks; Step 4, calculates factor of porosity parameter; Step 5, if rock unit breaks, calculates focus earthquake magnitude in conjunction with microseism focal mechanism; And step 6, repeating step 2, step 3, step 4 and step 5, complete the simulation in all moment.

Object of the present invention also can be achieved by the following technical measures:

Should the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter also comprise, before step 1, set up seepage-stress-damage coupling model of subsurface reservoir, for model is composed reservoir geology mechanics parameter.

In the step of seepage-stress-damage coupling model of setting up subsurface reservoir, the reservoir parameter governing equation that this seepage-stress-damage coupling model adopts is:

${\stackrel{\·}{\mathrm{\σ}}}_{\mathrm{ij}}=2G{\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{ij}}+(K-\frac{2G}{3}){\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{kk}}{\mathrm{\δ}}_{\mathrm{ij}}+\mathrm{\α}\stackrel{\·}{p}{\mathrm{\δ}}_{\mathrm{ij}}+{\mathrm{\γ}}_1\stackrel{\·}{T}{\mathrm{\δ}}_{\mathrm{ij}}---\left(1\right)$

$\stackrel{\·}{\mathrm{\ζ}}=\mathrm{\α}{\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{ii}}+\mathrm{\β}\stackrel{\·}{p}-{\mathrm{\γ}}_2\stackrel{\·}{T}---\left(2\right)$

σ in formula _ijσ _ijopening ε _ijrepresent respectively total stress and overall strain, p and T represent respectively pore pressure and temperature, and α represents Biot coefficient, and ζ represents saturation of pore fluid, δ _ijrepresent Kronecker symbol, K represents bulk modulus, and G represents modulus of shearing, γ ₁, γ ₂, the value of β is passed through formula below:

$\mathrm{\β}=\frac{\mathrm{\α}-\mathrm{\φ}}{K_s}+\frac{\mathrm{\φ}}{K_f}---\left(3\right)$

γ ₁=Kα _m （4）

γ ₂=αα _m+(α _f-α _m)φ （5）

φ represents factor of porosity, α _mand α _frepresent respectively the thermal expansivity of rock and fluid, the bulk modulus K of rock _srepresent, the bulk modulus of fluid is used K _frepresent; Suppose that fluid flows and follows Darcy's law in blowhole, Fourier law is followed in heat conduction; There is following formula:

$J^f=-{\mathrm{\ρ}}_f\frac{k}{\mathrm{\η}}\▿p---\left(6\right)$

$J^T=-k^T\▿T---\left(7\right)$ ρ _frepresent fluid density, k represents permeability, and η represents the coefficient of viscosity, k ^trepresent heat-conduction coefficient, J ^fand J ^trepresent respectively fluid flow and heat; Following formula (8) (9) is that in space, fluid flows and stress equilibrium equation;

σ _ij,j=0 （8）

$\frac{\∂\mathrm{\ζ}}{\∂t}=-\frac{1}{{\mathrm{\ρ}}_f}{\▿J}^f---\left(9\right)$

Bring governing equation above (1) (2) into balance equation (8) (9), obtain the field equation (10) (11) about rock deformation and fluid flow state;

$(K+\frac{G}{3})\▿(\▿.u)+{G\▿}^{2}u+m(\mathrm{\α}\▿p+{\mathrm{\γ}}_1\▿T)=0---\left(10\right)$

$\mathrm{\α}(\▿.\stackrel{\·}{u})+\mathrm{\β}\stackrel{\·}{p}-\frac{k}{\mathrm{\η}}{\▿}^{2}p-{\mathrm{\γ}}_2\stackrel{\·}{T}=0---\left(11\right)$

$\stackrel{\·}{T}+v(\▿T)-c^T{\▿}^{2}T=0---\left(12\right)$

U is displacement, m=[1 in the time that model is two dimension, 1,0] T, m=[1 when model is three-dimensional, 1,1,0,0,0] ^t, c ^tfor thermal diffusion coefficient, speed and the pore pressure of fluid are followed Darcy's law

In step 3, in model, reservoir rock is subject to the process after effect of stress can be described as elastic deformation and breaks two stages; While being subject to less stress, rock generation elastic deformation, this one-phase rock interior does not break; And in the time that the stressed increase of rock reaches the failure criteria of rock, rock starts to break, along with the development breaking, finally form crack.

In step 3, in elastic deformation-rupture mechanism, the process that the reducing of elastic modulus represented that rock breaks,

E=(1-d)E ₀ （13）

D represents the degree that rock interior breaks, and can be called rock fracture coefficient, E ₀the initial lithology modulus that represents rock, E is current lithology modulus; Occurred to break if rock is stressed, rock fracture coefficient can be explained by the surplus pressure of rock:

$d=1-\frac{f_{\mathrm{cr}}}{E_0\stackrel{\‾}{\mathrm{\ϵ}}}---\left(14\right)$

F _crfor the residual pressure of rock, for the strain occurring under corresponding pressure, represent initial compressive stress.

In step 4, obtain the actual loading situation of a certain each underground unit of moment, and contrast actual loading size and rock unit keep not breaking born maximum stress, the judgement of whether breaking, if do not broken, rock unit generation deformation, factor of porosity parameter changes according to deformation; If rock burst, factor of porosity is undergone mutation, and is converted into a larger numerical value, and this numerical value is constant.

In step 5, if broken, simulate the intensity of microseismic event according to the situation of change of stress, microseismic event source location is current computing unit position, the vibrations moment is current time.

Should the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter also comprise, after step 5, by all analog result output, as the foundation of analyzing and explain reservoir pressure.

The microearthquake event the Forward Modeling based on reservoir geology mechanics parameter in the present invention, compared with conventional microearthquake modeling algorithm, consider the variation of reservoir geology mechanics parameter in fracturing process, therefore result of calculation can reflect the actual change situation of subsurface reservoir really, can carry out by the method the prediction of microseismic event in subterranean fracture and fracturing process.Just drilling is that in simulation waterfrac treatment implementation process, reservoir is subject to the situation after STRESS VARIATION.While using this technology can simulate practice of construction operation, the information such as source location, source strength of microseismic event in generation, growth and the fracturing process in subsurface reservoir crack.These information are for instructing frac job to have great significance.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of a specific embodiment of the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter of the present invention;

Fig. 2 is model elastic modulus distribution plan in a specific embodiment of the present invention;

Fig. 3 is model stress envelope primitively in a specific embodiment of the present invention;

Fig. 4 is the model microseismic event schematic diagram that in a specific embodiment of the present invention, forward simulation obtains.

Embodiment

For above and other object of the present invention, feature and advantage can be become apparent, cited below particularly go out preferred embodiment, and coordinate appended graphicly, be described in detail below.

As shown in Figure 1, Fig. 1 is the process flow diagram of a specific embodiment of the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter of the present invention.

In step 101, set up seepage-stress-damage coupling model of subsurface reservoir, for model is composed reservoir geology mechanics parameter.

Must be in conjunction with hydrodynamic pressure to waterfrac treatment simulation, the be stressed description of deformation and rock failure process of rock.The generation of subterranean fracture is in the nature rock burst, and the tension force that its generation and development are subject to by rock mainly affects.The permeability of reservoir rock and stress are the functions of a coupling, and when after rock burst, permeability sharply increases;

The reservoir parameter governing equation that model of the present invention adopts as shown in the formula:

${\stackrel{\·}{\mathrm{\σ}}}_{\mathrm{ij}}=2G{\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{ij}}+(K-\frac{2G}{3}){\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{kk}}{\mathrm{\δ}}_{\mathrm{ij}}+\mathrm{\α}\stackrel{\·}{p}{\mathrm{\δ}}_{\mathrm{ij}}+{\mathrm{\γ}}_1\stackrel{\·}{T}{\mathrm{\δ}}_{\mathrm{ij}}---\left(1\right)$

$\stackrel{\·}{\mathrm{\ζ}}=\mathrm{\α}{\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{ii}}+\mathrm{\β}\stackrel{\·}{p}-{\mathrm{\γ}}_2\stackrel{\·}{T}---\left(2\right)$ σ in formula _ijσ _ijand ε _ijrepresent respectively total stress and overall strain, p and T represent respectively pore pressure and temperature, and α represents Biot coefficient, and ζ represents saturation of pore fluid, δ _ijrepresent Kronecker symbol, K represents bulk modulus, and G represents modulus of shearing, γ ₁, γ ₂, the value of β is passed through formula below:

$\mathrm{\β}=\frac{\mathrm{\α}-\mathrm{\φ}}{K_s}+\frac{\mathrm{\φ}}{K_f}---\left(3\right)$

γ ₁=Kα _m （4）

γ ₂=αα _m+(α _f-α _m)φ （5）

φ represents factor of porosity, α _mand α _frepresent respectively the thermal expansivity of rock and fluid, the bulk modulus K of rock _srepresent, the bulk modulus of fluid is used K _frepresent.Suppose that fluid flows and follows Darcy's law in blowhole, Fourier law is followed in heat conduction.There is following formula:

$J^f=-{\mathrm{\ρ}}_f\frac{k}{\mathrm{\η}}\▿p---\left(6\right)$

$J^T=-k^T\▿T---\left(7\right)$

ρ _frepresent fluid density, k represents permeability, and η represents the coefficient of viscosity, k ^trepresent heat-conduction coefficient, J ^fand J ^trepresent respectively fluid flow and heat.Following formula (8) (9) is that in space, fluid flows and stress equilibrium equation.

σ _ij,j=0 （8）

$\frac{\∂\mathrm{\ζ}}{\∂t}=-\frac{1}{{\mathrm{\ρ}}_f}{\▿J}^f---\left(9\right)$

Bring governing equation above (1) (2) into balance equation (8) (9), obtain the field equation (10) (11) about rock deformation and fluid flow state.

$(K+\frac{G}{3})\▿(\▿.u)+{G\▿}^{2}u+m(\mathrm{\α}\▿p+{\mathrm{\γ}}_1\▿T)=0---\left(10\right)$

$\mathrm{\α}(\▿.\stackrel{\·}{u})+\mathrm{\β}\stackrel{\·}{p}-\frac{k}{\mathrm{\η}}{\▿}^{2}p-{\mathrm{\γ}}_2\stackrel{\·}{T}=0---\left(11\right)$

$\stackrel{\·}{T}+v(\▿T)-c^T{\▿}^{2}T=0---\left(12\right)$

U is displacement, m=[1 in the time that model is two dimension, 1,0] ^t, m=[1 when model is three-dimensional, 1,1,0,0,0] ^t, c ^tfor thermal diffusion coefficient, speed and the pore pressure of fluid are followed Darcy's law

Flow process enters into step 102.

In step 102, for the pressure assignment of initial waterfrac treatment, to reservoir geology mechanics parameter initialize.Use equation (10)-(12) to be described individual grid cell, use finite element method (FEM) to carry out modeling.Flow process enters into step 103.

In step 103, change the rock element stress calculating of carrying out each particular moment according to the time.Flow process enters into step 104.

In step 104, according to stress calculating results, in conjunction with criterion in rock, judge whether current rock unit breaks.In model, reservoir rock is subject to the process after effect of stress can be described as elastic deformation and breaks two stages.While being subject to less stress, rock generation elastic deformation, this one-phase rock interior does not break.And in the time that the stressed increase of rock reaches the failure criteria of rock, rock starts to break, along with the development breaking, finally form crack.In elastic deformation-rupture mechanism, the process that the reducing of elastic modulus represented that rock breaks.

E=(1-d)E ₀ （13）

D represents the degree that rock interior breaks, and can be called rock fracture coefficient, E ₀the initial lithology modulus that represents rock, E is current lithology modulus.Occurred to break if rock is stressed, rock fracture coefficient can be explained by the surplus pressure of rock:

$d=1-\frac{f_{\mathrm{cr}}}{E_0\stackrel{\‾}{\mathrm{\ϵ}}}---\left(14\right)$

F _crfor the residual pressure of rock, for the strain occurring under corresponding pressure, represent initial compressive stress.

Carrying out reservoir geology mechanics parameter while describing, the original pressure of fluid, and the initial geology mechanics parameter of reservoir is as Poisson ratio, elastic modulus, initially stress etc. is all as known conditions.What need to solve is after hydrodynamic pressure changes, the situation of change of reservoir internal stress and strain.Use finite element method (FEM) solving equation (10) (11), and in the process solving, add mole of-coulomb of rock burst judgment criterion, just can obtain the response of reservoir under certain pressure break condition.Flow process enters into step 105.

In step 105, calculate, obtain the actual loading situation of a certain each underground unit of moment, and contrast actual loading size and rock unit keep not breaking born maximum stress, the judgement of whether breaking, if do not broken, rock unit generation deformation, factor of porosity parameter changes according to deformation.If rock burst, factor of porosity is undergone mutation, and is converted into a larger numerical value (this numerical value is constant).Flow process enters into step 106.

In step 106, if rock unit breaks, finally obtain microearthquake event information in conjunction with focal mechanism.If broken, simulate the intensity of microseismic event according to the situation of change of stress, microseismic event source location is current computing unit position, the vibrations moment is current time.Flow process enters into step 107.

In step 107, repeating step 103, to step 106, completes the simulation in all moment.Flow process enters into step 108.

In step 108, by all analog result output, as the foundation of analyzing and explain reservoir pressure.Flow process finishes.

For verification algorithm, set up one 500 meters wide, a two dimensional model of 500 meters long, dividing minimum grid unit is the square of 5 meters of the length of sides.Geomechanics parameter has been used certain work area known parameters.Fig. 2 is the elastic modulus distribution plan of model, the distribution plan that Fig. 3 is underground stress.Use invention algorithm to simulate to this model.Obtain the microseismic event distribution results figure shown in Fig. 4.

The invention provides in a kind of oil gas field waterfrac treatment process, microearthquake event simulation method based on reservoir geology mechanics parameter, produces variation and the microearthquake event information that will generate etc. of the further pressure break subsurface reservoir of analysis and prediction of microearthquake affair character while being mainly used in waterfrac treatment.The main flow process of the method is the state that the reservoir geology mechanics parameter model by setting up seepage-stress-damage coupling carrys out describing reservoir, by model formulation equation is solved under boundary condition, thereby realize the numerical simulation that waterfrac treatment process subsurface reservoir is changed, simulation will obtain the variation of subsurface reservoir parameter, comprise geomechanics parameter change, subterranean fracture distributes, and in conjunction with microearthquake focal mechanism principle, obtain the position that in fracturing process, microearthquake event produces, the information such as time and earthquake magnitude, just drilling the microearthquake event information of acquisition, for processing and explaining that the actual microearthquake data gathering in order to monitor subterranean fracture growth generation in waterfrac treatment process is significant.In order to use the stressed of math equation describing reservoir and the situation of breaking, method is done following hypothesis: reservoir has elasticity and fragility simultaneously, and its state uses elasticity damage mechanics to be described; The normal stress that reservoir rock is subject to and shearing stress are followed mole of-coulomb of fracture criteria; The permeability of reservoir is the elastically-deformable function that stress causes, rock break or tomography generate time, permeability will sharply increase.Under these assumed conditions, set up and meet the mathematical description equation that research requires.Under given boundary condition, just can, according to the equation solution reservoir situation of breaking, understand and grasp the distribution of subterranean fracture.

Claims (8)

1. the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter, is characterized in that, should the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter comprise:

Step 1, is the pressure assignment of initial waterfrac treatment, uses finite element method (FEM) to carry out modeling;

Step 2, changes the rock element stress calculating of carrying out each particular moment according to the time;

Step 3, according to stress calculating results, in conjunction with criterion in rock, judges whether current rock unit breaks;

Step 4, calculates factor of porosity parameter;

Step 5, if rock unit breaks, calculates focus earthquake magnitude in conjunction with microseism focal mechanism; And

Step 6, repeating step 2, step 3, step 4 and step 5, complete the simulation in all moment.

2. the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter according to claim 1, it is characterized in that, should the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter also comprise, before step 1, set up seepage-stress-damage coupling model of subsurface reservoir, for model is composed reservoir geology mechanics parameter.

3. the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter according to claim 1, it is characterized in that, in the step of seepage-stress-damage coupling model of setting up subsurface reservoir, the reservoir parameter governing equation that this seepage-stress-damage coupling model adopts is:

${\stackrel{\·}{\mathrm{\σ}}}_{\mathrm{ij}}=2G{\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{ij}}+(K-\frac{2G}{3}){\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{kk}}{\mathrm{\δ}}_{\mathrm{ij}}+\mathrm{\α}\stackrel{\·}{p}{\mathrm{\δ}}_{\mathrm{ij}}+{\mathrm{\γ}}_1\stackrel{\·}{T}{\mathrm{\δ}}_{\mathrm{ij}}---\left(1\right)$

$\stackrel{\·}{\mathrm{\ζ}}=\mathrm{\α}{\stackrel{\·}{\mathrm{\ϵ}}}_{\mathrm{ii}}+\mathrm{\β}\stackrel{\·}{p}-{\mathrm{\γ}}_2\stackrel{\·}{T}---\left(2\right)$ σ in formula _ijσ _ijand ε _ijrepresent respectively total stress and overall strain, p and T represent respectively pore pressure and temperature, and α represents Biot coefficient, and ζ represents saturation of pore fluid, δ _ijrepresent Kronecker symbol, K represents bulk modulus, and G represents modulus of shearing, γ ₁, γ ₂, the value of β is passed through formula below:

$\mathrm{\β}=\frac{\mathrm{\α}-\mathrm{\φ}}{K_s}+\frac{\mathrm{\φ}}{K_f}---\left(3\right)$

γ ₁=Kα _m （4）

γ ₂=αα _m+(α _f-α _m)φ （5）

φ represents factor of porosity, α _mand α _frepresent respectively the thermal expansivity of rock and fluid, the bulk modulus K of rock _srepresent, the bulk modulus of fluid is used K _frepresent; Suppose that fluid flows and follows Darcy's law in blowhole, Fourier law is followed in heat conduction; There is following formula:

$J^f=-{\mathrm{\ρ}}_f\frac{k}{\mathrm{\η}}\▿p---\left(6\right)$

$J^T=-k^T\▿T---\left(7\right)$ ρ _frepresent fluid density, k represents permeability, and η represents the coefficient of viscosity, k ^trepresent heat-conduction coefficient, J ^fand J ^trepresent respectively fluid flow and heat; Following formula (8) (9) is that in space, fluid flows and stress equilibrium equation;

σ _ij,j=0 （8）

$\frac{\∂\mathrm{\ζ}}{\∂t}=-\frac{1}{{\mathrm{\ρ}}_f}{\▿J}^f---\left(9\right)$

Bring governing equation above (1) (2) into balance equation (8) (9), obtain the field equation (10) (11) about rock deformation and fluid flow state;

$(K+\frac{G}{3})\▿(\▿.u)+{G\▿}^{2}u+m(\mathrm{\α}\▿p+{\mathrm{\γ}}_1\▿T)=0---\left(10\right)$

$\mathrm{\α}(\▿.\stackrel{\·}{u})+\mathrm{\β}\stackrel{\·}{p}-\frac{k}{\mathrm{\η}}{\▿}^{2}p-{\mathrm{\γ}}_2\stackrel{\·}{T}=0---\left(11\right)$

$\stackrel{\·}{T}+v(\▿T)-c^T{\▿}^{2}T=0---\left(12\right)$

U is displacement, m=[1 in the time that model is two dimension, 1,0] ^t, m=[1 when model is three-dimensional, 1,1,0,0,0] ^t, c ^tfor thermal diffusion coefficient, speed and the pore pressure of fluid are followed Darcy's law $v=-\frac{k}{\mathrm{\η}}\▿p.$

4. the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter according to claim 1, is characterized in that, in step 3, in model, reservoir rock is subject to the process after effect of stress can be described as elastic deformation and breaks two stages; While being subject to less stress, rock generation elastic deformation, this one-phase rock interior does not break; And in the time that the stressed increase of rock reaches the failure criteria of rock, rock starts to break, along with the development breaking, finally form crack.

5. the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter according to claim 4, is characterized in that, in step 3, and in elastic deformation-rupture mechanism, the process that the reducing of elastic modulus represented that rock breaks,

E=(1-d)E ₀ （13）

D represents the degree that rock interior breaks, and can be called rock fracture coefficient, E ₀the initial lithology modulus that represents rock, E is current lithology modulus; Occurred to break if rock is stressed, rock fracture coefficient can be explained by the surplus pressure of rock:

$d=1-\frac{f_{\mathrm{cr}}}{E_0\stackrel{\‾}{\mathrm{\ϵ}}}---\left(14\right)$

F _crfor the residual pressure of rock, for the strain occurring under corresponding pressure, represent initial compressive stress.

6. the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter according to claim 1, it is characterized in that, in step 4, obtain the actual loading situation of a certain each underground unit of moment, and contrast actual loading size and rock unit keep not breaking born maximum stress, and the judgement of whether breaking, if do not broken, rock unit generation deformation, factor of porosity parameter changes according to deformation; If rock burst, factor of porosity is undergone mutation, and is converted into a larger numerical value, and this numerical value is constant.

7. the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter according to claim 1, it is characterized in that, in step 5, if broken, simulate the intensity of microseismic event according to the situation of change of stress, microseismic event source location is current computing unit position, and the vibrations moment is current time.

8. the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter according to claim 1, it is characterized in that, should the microearthquake event the Forward Modeling based on reservoir geology mechanics parameter also comprise, after step 5, by all analog result output, as the foundation of analyzing and explain reservoir pressure.